Bobbin supporting device



H. ADAM BOBBIN SUPPORTING DEVICE Jan. 20, 1959 Filed Dec. 1:5, 1955 2 Sheets-Sheet 1 Jan. 20, 1959 H. ADAM BOBBIN SUPPORTING DEVICE 2 Shets-Sheer. 2

Filed Dec. 13, 1955 Ar f/vr,

BOBBIN SUPPQRTING DEVICE Hermann Adam, liieiefeld, Germany Application December 13, 1955, Serial No. 552,886

Claims priority, application Germany December 17, 1954 7 Claims. (Ql. 112-231) The invention relates to a bobbin case gripping or holding device for sewing machines. It is known, for the purpose of insuring relatively silent operation of sewing machines, to provide only such a clearance or gap between the bobbin case support or stay, and the bobbin case, that the thread can slide through between them. For this purpose it is likewise known to make the flap of the gripping device, which is pivoted on the support, adjustable relative to the bobbin case. These known adjustment means do not satisfy this purpose sufiiciently, or the manipulation of these adjusting means is more or less difiicult, so that setting up of the proper adjustment requires adequate skill and extensive testing.

These shortcomings are to be eliminated in accordance with the invention which resides primarily in the feature of the cover or flap comprising a bobbin case support and a separate pivot member in a manner that these two components are connected with each other by means of an adjustable ball joint.

This ball joint is centrally mounted so that the bobbin case support is universally movable in the ball joint support or hearing of the pivot member. In this manner it is achieved that the bobbin case support can adapt itself so accurately to the corresponding opposite surface on the bobbin case that the desideratum of a small air gap between case and bobbin case support or stay can be obtained evenly.

The position of the bobbin case support with respect to its pivotable member is suitably made to be fastened by means of a screw connection. In accordance with one object of the invention a particularly simple embodiment is provided if the bobbin case support and the pivot member are connected in the ball joint by means of a head screw which is adjustably mounted in the pivot member with tolerance.

In addition, another object of the invention provides that the bobbin case support is not turned radially as the fastening means are loosened. For this purpose a suitable supporting device is to be provided which does not interfere with the universal movability of the bobbin case support in the pivot members.

Accordingly, it is an additional object of the invention to provide in the pivot member an eccentric ball screw having a ball head which is in engagement with a cut out or recess in the bobbin case support.

Alone by means of this arrangement, a particularly noiseless manner of operation of the sewing machine is insured which is the result of the development of the smallest possible play between bobbin case and bobbin case support. However, the noiselessness can still be increased by making the bobbin case support and, in some cases, the pivot member of a noise suppressing plastic.

For this purpose it is desirable to provide the components which consist of plastic with metal inserts to increase the stability of these parts. On the other hand, these metal inserts can also be utilized for the purpose of accommodating the threads for the screw fastening means,

2,35,496 Patented Jan. 26, 1959 In accordance with a further object of the invention the device can also be arranged in a manner that the bobbin case support or stay is simultaneously constructed as a pivot member in the form of a face ring having a spherically shaped surface adapted to be turned in all directions and mounted inside the flap. In this embodiment an additional securing means for the face ring may be provided on the flap. Inasmuch as the face ring is journalled directly in the flap with its spherically shaped surface, a separate mounting of a bobbin case support beside the actual flap is eliminated. This affords first of all a simplification of the gripping or stay device as compared to the embodiments described above. The securing means serves for the purpose of locking the attained adjusted setting of the face ring with respect to the bobbin case.

It is especially advantageous if the face ring is provided with three projecting beads at its surface which faces the bobbin case. This insures that the thread sweeps only along these three points and need no longer to slide along the entire circumference of the embossed disk as heretofore.

In addition to this it is advantageous to provide at the support which is connected to the plate of the machine an eccentric screw for the exact guided setting of the thread gap between front ring and bobbin case. For this purpose the securing screw for connecting the support to the plate of the machine is guided in a slot.

While using the support device in accordance with Figs. 4 and 5 the face ring is first set to the position cor responding to the front surface of the bobbin case by means of the spherical bearing surface of this face ring. Thereupon the attained position of the face ring can be secured by the fastening means. Subsequently the particular thread gap is set by operation of the aforementioned eccentric screw. if the eccentric screw is rigidly set the position of the support on the plate of the machine is secured by tightening the associated fastening screw.

The drawings illustrate three embodiments of the subject of the application and in particular,

Fig. 1 shows a front view of a bobbin case supporting arrangement looking upon the stay support and the pivot member;

Fig. 2 shows a side view of the supporting arrangement in accordance with Fig. 1 with a partial cross section along line IIII of Fig. 1; I

Fig. 3 is a view substantially as in Fig. 2, also in section of a different embodiment of a device;

Fig. 4 illustrates a third embodiment of a bobbin case support looking at the front of the support;

Fig. 5 is a sectional view of the bobbin case support in accordance with Fig. 4, taken along the line V-V,

Fig. 6 is a detail illustrating the open position of the support; and

Fig. 7 illustrates the relationship of parts 31, 33 and 36.

The gripping arrangement comprises the bobbin gripper support or retainer 1 with the pivot member 2. The pivot member 2 is pivotally mounted on the support 3 by means of stud 4. The bobbin gripper support or retainer is connected with the pivot member 2 by means of head screw 5. In particular the central portion of the bobbin case support 1 is provided at the outer surface of the support and the pivot member 2 at its coordinated inner surface with a spherical surface arrangement. The thread portion 6 of the head screw 5 is guided in the pivot member 2 with tolerance. The head screw 5 has also a base or washer 8. Upon loosening the head screw 5 the bobbin case support can thus be moved in different directions in this ball joint. Thus the embossed ring 9 on the bobbin case support 1 can evenly adjust itself with respect to the front surface 1d of the bobbin case 11.

In order to prevent turning of the bobbin case support or retainer with respect to pivot member 2 when the screw connection is loosened an eccentric ball head screw 12 is provided having a nut 13 for securing the ball head in position. The ball head 14 is disposed in a slot 15 of the bobbin case support 1. -This form of securing the bobbin case support or retainer against turning with respect to pivot member 2 is chosen for the pr of avoiding interference with the universal movabiiity oi the bobbin case retainer l-l relative to the pivot member 2 in the ball joint 5, e. The securing of the bobbin case against displacement with respect to the bobbin case retainer is achieved in a known manner by means of 1: lug 16 which engages a corresponding slot in the bobbin case.

The bobbin case retainer is made of a noise suppressing artificial material, chosen preferably from the group of the polyamides. In this bobbin case retainer there is a steel insert '7 having a central portion which corresponds to the spherical surface of the retainer but which is also provided With a thread to receive the thread of the head screw the pivot member 2 may be made of the same material and may likewise be provided with a steel insert 13.

If the support is to be opened, light pressure is applied with the operators thumb upon the grip 19 of pivot member 2 against which the pressure of spring 24} is effective. For the closed condition of the bobbin case retainer this leaf spring 2t rests against the hinge member 22 of the pivot member 2. The open position of the bobbin case support or retainer is shown by the dot and dash lines in Figs. 2 and 3. In this position the member 23 rests against the abutment 24 on the support 3.

In the embodiment in accordance with Fig. 3 the bobbin casc support 25 is made of steel as is the pivot member 26, A contact disk 27 made of any suitable material such as metal or synthetic resin is provided in the bobbin case support which is held in position against an intermediate felt ring 23 and a spring 29. In all other respects the construction of the embodiment in accordance with Fig. 3 corresponds to the embodiment in accordance with Figs. 1 and 2 described above.

In accordance with the embodiment illustrated in Figs. 4 and 5 the bobbin case supporting means comprise the flap 31 which is pivotably mounted on the base 32 by means of a pin 33. The base 32 is secured by means of head screw 34 to the plate 35 of the sewing machine.- A pressure ring disk 36 is disposed in front of the flap 3 which is adjusted to the correct position by means of shoulder screws 37, 38 to permit substantially universal movement of face ring 59 as the face ring 39 is held between disk 36 and flap 31 The central portion of the flap 3?. and of the pressure ring disk 36 present a spherical surface 4% in the manner of a bearing shell which is engaged by the face ring 39 which presents a corresponding outer spherical surface 41. Thus the rockable face ring 39 can position itself evenly by means of the three beads d2, 43 and 4-4 against the front surface 45 of the bobbin case 46.

The face ring or rockablc member 39 is first placed in the flap 31, whereupon the ring disk 36 is placed on the other side and drawn up by means of screws 37, 3% in a manner that the face ring 39 is free to adapt itself with its beads 42, 43 and 44 to the surface 45 of the bobbin case 46.

An eccentric screw 48 is provided which is guided in the base 32 to provide sufiicient clearance for the thread to slide behind the bobbin case 46. Turning the screw 48 after loosening head screw 34 permits adjustment of the proper clearance. The head screw 34 is tightened again after correct adjustment is made. The head screw 34 is guided in a slot 47 of the base 32.

The face ring 39 is preferably madeof a noise suppressing substance, preferably one of the polyamides.

The bobbin case 46 is secured against rotating by means of a suitably shaped steel wire spring 49 which is secured to the flap 31 by means of head screw 53 and engages a corresponding slot in the bobbin case with its projecting end 51. The arcuate shaping of this spring provides at the same time for elastic yielding in the slot of the bobbin case during sewing and contributes considerably to the noise suppression.

If it is desired to open the bobbin case support or retainer a slight pressure is exerted upon the projecting lobe 52 of the flap 31 which is under pressure applied by bolt 53 and spring 54 associated therewith. The open position of the bobbin case support is shown in dot and dash lines. Here the nose 56a rests against the abutm L 57 of the base 32. In this position the bobbin case is separated from the rotary shuttle and would be free to slide downwardly. Two pins 58, 59 secured to disk 36 restrain the bobbin case from sliding out of the support.

As indicated in Fig. 5 these pins 58, 59 extend. at right angles to the disk 36 and below the bobbin case. It the flap 31 is moved into the position shown in Fig. 6 these pins extend obliquely upward and the bobbin case rests likewise in oblique position on the face ring 39, supported by pins 58, 59.

Having described my invention with reference to the embodiments illustrated, I do not wish to be limited thereto but what I desire to protect by Letters Patent is set forth in the appended claims.

I claim:

1. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a flap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally of said retainer intermediate said fiap and said bobbin case, said retainer and said flap presenting spherical surfaces defining an adjustable joint therebetween, and connecting means presenting at one end a shoulder portion freely seated rearwardly of said fiap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said flap in a manner permitting accurate seating of said retainer 0n the adjacent surface of said bobbin case.

2. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a flap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally of said retainer intermediate said flap and said bobbin case, said retainer and said flap presenting spherical surfaces defining an adjustable joint therebetween, and connecting means presenting at one end a shoulder portion freely seated rearwardly of said flap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said flap in a manner permitting accurate seating of said retainer on the adjacent surface of said bobbin case, said bobbin case retainer defining a slot and an eccentric ball head screw being secured to said flap and having its ball head disposed in said slot for adjustment of the position of said retainer relative to said flap.

3. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a flap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally of said retainer intermediate said flap and said bobbin case, said retainer and said flap presenting spherical surfaces defining an adjustable joint therebetween, and connecting screw means presenting at one end a shoulder portion freely seated rearwardly of said flap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said fiap in a manner permitting accurate seating of said retainer on the adjacent surface of said bobbin case, said retainer being made of a noise suppressing artificial material and including a metal insert provided with a thread to receive said other end of said connecting screw means.

4. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a flap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally of said retainer intermediate said flap and said bobbin case, said retainer and said fiap presenting spherical surfaces defining an adjustable joint therebetween, and connecting means presenting at one end a shoulder portion freely seated rearwardly of said flap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said flap in a manner permitting accurate seating of said retainer on the adjacent surface of said bobbin case, said retainer being defined by an annular member presenting a spherical surface and said flap having a corresponding spherical surface to receive and adjustably support said annular member.

5. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a fiap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally of said retainer intermediate said flap and said bobbin case, said retainer and said flap presenting spherical surfaces defining an adjustable joint therebetween, and connecting means presenting at one end a shoulder portion freely seated rearwardly of said flap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said fiap in a manner permitting accurate seating of said retainer on the adjacent surface of said bobbin case, said retainer being defined by an annular member presenting a spherical surface and said flap having a corresponding spherical surface to receive and adjustably support said annular member, and said annular member being provided with three beads upon its surface confronting the bobbbin case.

Cit

6. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a flap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally of said retainer intermediate said flap and said bobbin case, said retainer and said flap presenting spherical surfaces defining an adjustable joint therebetween, and connecting means presenting at one end a shoulder portion freely seated rearwardly of said flap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said fiap in a manner permitting accurate seating of said retainer on the adjacent surface of said bobbin case, said retainer being defined by an annular member presenting a spherical surface and said flap having a corresponding spherical surface to receive and adjustably support said annular member, said annular member being provided with three beads upon its surface confronting the bobbin case, said device being mounted upon a base having a slot and said base being secured to the plate of the sewing machine for support, a shoulder screw being provided and extending through said slot into the plate of the machine and a cam screw extending through said base into the plate of the machine to permit adjustment of said base.

7. In a sewing machine having a bobbin mounted in a bobbin case, a bobbin supporting device of the type having a flap pivotally supported on a base proximate the lower peripheral portion of the bobbin case for pivotal movement relative thereto, said flap carrying a bobbin case retainer, means supporting said bobbin case retainer on said flap in nested relationship with said flap centrally I of said retainer intermediate said flap and said bobbin case, said retainer and said flap presenting spherical surfaces defining an adjustable joint therebetween, and connecting means presenting at one end a shoulder portion freely seated rearwardly of said flap and at the other end a portion extending freely through said flap and having firm engagement with said retainer to provide for sliding engagement between said spherical surfaces and supporting said retainer upon said flap in a manner permitting accurate seating of said retainer on the adjacent surface of said bobbin case, said retainer being defined by an annular member presenting one said spherical surface, said flap having an abutment conformation and said base presenting an abutment for engagement by said conformation for the disengaged position of said flap and said retaining member.

References Cited in the file of this patent UNITED STATES PATENTS 

